Modern birds
Black- ( Thalassarche melanophris )
- Urkiefervögel ( Palaeognathae )
- Neukiefervögel ( Neognathae )
The Neornithes ( Recent birds or Latter-day birds - also called " modern birds " ) comprise a subset of the class of birds all modern-day birds, all extinct birds of the Cenozoic as well as some species of birds of the Cretaceous period. The taxon ( systematic unity ) has been held since its introduction by Gadow (1893 ), especially in the Paläornithologie in the demarcation of modern bird groups of extinct bird groups of the Mesozoic use.
In the Rezentbiologie " birds " ( Aves ) is often used synonymously as a group name to the group Neornithes. Only after the definition of Gauthier (1986 ) Aves and Neornithes are actually synonyms. Gauthier leads instead to the group of all fossil and extant birds the designation Avialae.
Features
Modern birds have to Hope (2002) derived the following common characteristics: fusion of the maxillary and Prämaxillarknochen; the maxilla is greatly reduced and primarily limited to the palate region; the Mandibularsymphysen are fused together; Merging Dental and Surangulare; the absence of teeth; the shoulder joint pit of the Raven leg is not laterally more extended than the shoulder blade approach leg of the Raven; the shoulder joint pit on the shoulder blade is the side or front - side - oriented; the shoulder joint pit of the Raven leg is completely separated, in part or that of the scapula; the shoulder joint head is large; the depression of the humeral ligament pronounced; the Deltopectoralkamm of the upper arm is bent forward and the Pneumotricipitalvertiefung is perforated due to a pneumatic opening.
Phylogenesis
As the oldest reliable evidence of the Neornithes applies Vegavis iaai, a goose bird whose fossils ( Clarke, among others 2005) were discovered in sedimentary rocks of the Antarctic Vega Island. The formation time of the fossil occurrence falls in the Maastrichtian. It more representative of modern bird orders from the Upper Cretaceous period have been described, but are all considered doubtful due to the fragmentary preservation of the underlying fossils.
Whether the radiation of Neornithes essentially took place before or after the Cretaceous - Tertiary boundary, is controversial: while the lack of fossil evidence from the Cretaceous period and the occurrence of all modern systems in the Paleocene and Eocene (eg Dyke among others 2004) as evidence is evaluated for a diversification of Neornithes after the mass extinction at the end of the Cretaceous ( Feduccia 2003), indicate all molecular biological findings consistent to an origin of modern bird orders long before the end of the Cretaceous back (eg Slack, among others in 2006, Harrison, among others 2004). After a model that carries both paleontological and molecular biological results into account, there was a variety of lineages of modern birds since the Cretaceous period, however, the ecological diversification within individual modern groups occurred only at the beginning of the Tertiary (Harrison, among others 2004).
According to this view already diverged in the Cretaceous period about 100 million years ago, the two sub-groups occurring today the Neornithes, the flightless Urkiefervögel ( Palaeognathae ) and the Neukiefervögel ( Neognathae ). The morphologically similar to each other groups of gallinaceous birds ( Galliformes ) and Anseriformes ( Anseriformes ) ( anatomical comparison, see Dzerzhinsky 1995) form the taxon Galloanserae whose stem form in the early Late Cretaceous of the root form of the Neoaves, which include all other groups of birds of Neukiefervögel, separated.
The systematics of birds presents itself, including the group Pygostylia and new findings on the family relationships of Mesozoic birds as follows:
? Oviraptorosaurier (not too loud birds Fastovsky and Weishampel 2005)
Patagopteryx
Vorona
Hesperornithiformes
Ichthyornithiformes
Neornithes ( " Aves " by Fastovsky and Weishampel 2005)
Archaeopterygidae